--- ImageOutputDev.cc.pbm-invert	2008-03-26 21:38:52.000000000 +0200
+++ ImageOutputDev.cc	2008-08-06 00:44:43.000000000 +0300
@@ -103,10 +103,13 @@ void ImageOutputDev::drawImage(GfxState 
   FILE *f;
   ImageStream *imgStr;
   Guchar *p;
+  Guchar zero = 0;
+  GfxGray gray;
   GfxRGB rgb;
   int x, y;
   int c;
   int size, i;
+  int pbm_mask = 0xff;
 
   // dump JPEG file
   if (dumpJPEG && str->getKind() == strDCT &&
@@ -149,10 +152,16 @@ void ImageOutputDev::drawImage(GfxState 
     // initialize stream
     str->reset();
 
+    // if 0 comes out as 0 in the color map, the we _flip_ stream bits
+    // otherwise we pass through stream bits unmolested
+    colorMap->getGray(&zero, &gray);
+    if(colToByte(gray))
+      pbm_mask = 0;
+
     // copy the stream
     size = height * ((width + 7) / 8);
     for (i = 0; i < size; ++i) {
-      fputc(str->getChar(), f);
+      fputc(str->getChar() ^ pbm_mask, f);
     }
 
     str->close();